“Specifically, EMA says the diseases pose a significant challenge for drugmakers to study, as all three have a long progression and symptoms that are either unspecific or non-predictive of long-term outcomes. Furthermore, EMA says the use of "hard" clinical outcomes like liver transplantation or death raise feasibility issues for studies, and the need for repeated liver biopsies deters patients from enrolling in studies and increases risk.

Because of these challenges, EMA says there is a strong need for a validated surrogate endpoint to reduce the need for biopsies.”